A pulse reference X-ray reference radiation field generating device based on a steady-state X-ray machine

Abstract

The present invention relates to a pulse reference X-ray reference radiation field generating device based on a steady-state X-ray machine, belonging to the field of pulse radiation testing technology, comprising a steady-state X-ray machine and a shielding support body placed outside the steady-state X-ray machine, a ray exit port being opened on the shielding support body, the ray exit port being located on the axis of the radiation field generated by the steady-state X-ray machine, a pulse shutter, a radiation quality and a beam limiting aperture being sequentially arranged outside the shielding support body along the axis of the radiation field of the steady-state X-ray machine, the pulse shutter being adjacent to the ray exit port; the continuous X-rays generated by the steady-state X-ray machine are output as pulse X-rays through the cutting of the pulse shutter, the pulse X-rays are filtered by the radiation quality to generate pulse filtered beam X-rays, thereby forming a pulse X-ray reference radiation field. The pulse reference radiation field device provided by the present invention can realize the radiation performance parameter test of the nuclear radiation dosimeter under the pulse dynamic part and the nuclear critical accident alarm system test, etc., and solve the traceability problem of the measuring instrument for pulse radiation dose monitoring.

Description

Technical Field

[0001] The present invention belongs to the technical field of pulse radiation testing, and in particular relates to a pulse reference X-ray reference radiation field generating device based on a steady-state X-ray machine. Background Art

[0002] International research on radiation protection dosimetry is mainly focused on continuous radiation, but pulsed radiation has been widely used in industrial flaw detection, X-ray diagnosis and scientific research. Pulsed radiation has a wide range of applications in nuclear technology fields such as the development of new detectors, pulsed ionizing radiation measurement, transient imaging and nuclear accident emergency response.

[0003] Active electronic dosimeters are widely used for dose monitoring of ionizing radiation. Their direct-reading display and alarm functions provide important monitoring methods for radiation practitioners. Active electronic dosimeters are divided into many types based on radiation detection methods, including GM counter type, scintillator detector type, semiconductor detector type and ionization chamber type, with real-time display and dose alarm functions. Pulsed X-rays have the characteristics of short duration and high instantaneous dose rate, and their radiation dose measurement is extremely difficult. Taking ns-level radiation pulses as an example, the single pulse dose often reaches more than 1μSv, and the instantaneous dose rate can reach 10 5 Sv / h or more. For GM counters, semiconductor detectors, etc., there are measurement accumulation and detection dead time problems, which make it difficult to achieve such a high dose rate response, that is, the instrument has an over-response problem, which will inevitably affect the accuracy of the monitoring results; active electronic dosimeters have a measurement time cycle. In order to reduce the energy consumption of the dosimeter, the interval between two measurement cycles can be up to several seconds. If the pulse radiation occurs within the interval of the instrument measurement cycle, it is very likely that an omission event will occur, which will greatly affect the accuracy of the measurement result and cause the measurement result to be seriously low; an accident in which a person accidentally enters a radiation field is also a large-dose pulse event for active personal dosimeters. In addition, a nuclear criticality accident is also a typical pulse radiation. A nuclear criticality accident refers to an unexpected critical or supercritical event caused by some unexpected reason in a system containing fissile materials. Taking a typical nuclear criticality accident as an example, a total of about 10 19 The fission occurred about 10 times in the first 0.5 seconds. 18 The fissions continue for several hours, with a fission pulse generated every 10 minutes, and each fission lasts no longer than 0.5 seconds. Therefore, the neutrons, X-rays and gamma rays produced by nuclear criticality accidents are typical pulse radiation.

[0004] Pulse radiation dose testing is extremely difficult, and existing measurement and testing technologies lag far behind the needs of pulse radiation field application technology, which directly affects the performance of related pulse radiation fields. At the same time, the lack of pulse standard radiation fields also restricts the development of pulse testing technology. Carrying out research on related calibration technologies has become an important direction for the future development of my country's ionizing radiation measurement and transmission system. Therefore, this invention is of great significance for solving the traceability problem of measuring instruments for pulse radiation dose monitoring.

[0005] IEC60846-1:2009 states that the response time of an active radiation dosimeter should not be greater than 10 seconds, so the present invention classifies ionizing radiation with a duration of less than 10 seconds as pulse radiation. Pulse X-rays in the fields of medical diagnosis, material testing, radiographic inspection, and scientific research are classified as shown in Table 1.

[0006] Table 1 Typical pulse radiation parameters

[0007]

[0008] Millisecond pulse X-rays are mainly used in fields such as radiological diagnosis, radiographic flaw detection, and personnel and object detection, and have a wide range of applications; microsecond pulse X-rays are mainly generated by electron accelerators and are mainly used in fields such as radiotherapy and irradiation processing; nanosecond pulse X-rays are mainly used in fields such as flash X-ray technology, transient imaging, and object detection. Summary of the invention

[0009] In order to solve the defects of the prior art, the purpose of the present invention is to provide a pulse reference X-ray reference radiation field generating device based on a steady-state X-ray machine, which can realize the radiation performance parameter testing of nuclear radiation dosimeters under pulsed dynamic parts and solve the traceability problem of measuring instruments for pulse radiation dose monitoring.

[0010] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0011] A pulse reference X-ray reference radiation field generating device based on a steady-state X-ray machine, comprising a steady-state X-ray machine and a shielding support body disposed outside the steady-state X-ray machine, wherein a ray exit port is formed on the shielding support body, and the ray exit port is located on the axis of the radiation field generated by the steady-state X-ray machine, and a pulse shutter, a radiation quality and a beam limiting aperture are sequentially arranged outside the shielding support body along the axis of the radiation field of the steady-state X-ray machine, and the pulse shutter is adjacent to the ray exit port;

[0012] The continuous X-rays generated by the steady-state X-ray machine are output as pulsed X-rays through the cutting of the pulse shutter, and the pulsed X-rays are filtered by the radiation quality to generate pulsed filtered beam X-rays, thereby forming a pulsed X-ray reference radiation field.

[0013] Furthermore, in the pulse reference X-ray reference radiation field generating device based on the steady-state X-ray machine as described above, the pulse shutter includes a high-speed cylinder, the piston rod end of the high-speed cylinder is connected to the cylinder bracket, the cylinder bracket is connected to the tungsten alloy shutter, and the cylinder bracket is installed on a slide rail. The linear reciprocating motion of the high-speed cylinder piston rod drives the tungsten alloy shutter to perform linear reciprocating motion, thereby controlling the opening and closing of the ray outlet, thereby realizing the pulse output of X-rays.

[0014] Furthermore, the pulse reference X-ray reference radiation field generating device based on the steady-state X-ray machine as described above adjusts the pulse width of the pulse X-ray by adjusting the travel speed of the high-speed cylinder piston rod and the shutter opening size.

[0015] Furthermore, in the pulse reference X-ray reference radiation field generating device based on the steady-state X-ray machine as described above, the travel speed range of the high-speed cylinder piston rod is 0.01m / s-50m / s and by adjusting the shutter opening size, the pulse width range of the corresponding output single pulse X-ray is 0.1ms-10s.

[0016] Furthermore, in the pulse reference X-ray reference radiation field generating device based on the steady-state X-ray machine as described above, the radiation mass is used to filter out the low-energy part of the pulse X-ray to form a pulse filtered beam X-ray reference radiation.

[0017] Furthermore, in the pulse reference X-ray reference radiation field generating device based on a steady-state X-ray machine as described above, the number of the radiation materials is multiple and evenly distributed on the circumference of a rotatable wheel. The performance parameters of the multiple radiation materials are different. According to the needs, the appropriate radiation material is rotated to the axis of the pulse X-ray radiation field to obtain different pulse filtered beam X-ray reference radiations.

[0018] Furthermore, in the pulse reference X-ray reference radiation field generating device based on a steady-state X-ray machine as described above, the number of the beam limiting apertures is two, and a supervisory ionization chamber is also provided between the two beam limiting apertures.

[0019] Furthermore, the pulse reference X-ray reference radiation field generating device based on the steady-state X-ray machine as described above controls the divergence angle of the pulse filtered beam X-ray within a set range through the beam limiting aperture; and monitors the stability of the pulse filtered beam X-ray field through the monitoring ionization chamber.

[0020] Furthermore, the pulse reference X-ray reference radiation field generating device based on the steady-state X-ray machine as described above reduces X-ray scattered radiation and prevents radiation leakage through the shielding support body.

[0021] Furthermore, as described above, the pulse reference X-ray reference radiation field generating device based on the steady-state X-ray machine, the pulse reference X-ray radiation field generated by the device has a diameter ranging from 7 cm to 70 cm.

[0022] The pulse reference X-ray reference radiation field generating device of the present invention has the following significant technical effects:

[0023] The present invention establishes a pulse reference radiation field based on a steady-state X-ray machine, which can realize the radiation performance parameter test of the nuclear radiation dosimeter under pulse dynamic parts, and solves the traceability problem of the measuring instrument for pulse radiation dose monitoring; the pulse width of the established pulse X-ray reference radiation field is adjustable between 0.1ms-10s, which can be used to carry out research on the pulse radiation response characteristics of various radiation protection instruments and personal dosimeters, and can also be used to carry out testing, calibration and verification of nuclear accident critical alarm systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure of a device for establishing a pulse reference radiation field based on a steady-state X-ray machine provided in a specific embodiment of the present invention;

[0025] Figure 2 yes Figure 1 Schematic diagram of the structure of the medium pulse shutter;

[0026] In the figure: 1-steady-state X-ray machine; 2-shielding support; 3-pulse shutter; 4-radiation mass; 5-beam limiting aperture; 6-monitoring ionization chamber; 31-high-speed cylinder; 32-slide rail; 33-cylinder bracket; 34-tungsten alloy shutter. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is further described below in conjunction with specific embodiments and the accompanying drawings.

[0028] Figure 1 The schematic diagram of the structure of the device for establishing a pulsed X-ray reference radiation field based on a steady-state X-ray machine is shown. The device includes a steady-state X-ray machine 1, a shielding support body 2 is arranged outside the steady-state X-ray machine 1, a ray exit port is opened on the shielding support body 2, and the ray exit port is located on the axis of the radiation field generated by the steady-state X-ray machine. A pulse shutter 3, a radiation quality 4, two collimating apertures 5 and a monitoring ionization chamber 6 are arranged in sequence outside the shielding support body 2 along the axis of the radiation field of the steady-state X-ray machine, wherein the pulse shutter 3 is adjacent to the ray exit port, and the monitoring ionization chamber 6 is located between the two collimating apertures 5. The continuous X-rays generated by the steady-state X-ray machine 1 are output as pulsed X-rays through the cutting of the pulse shutter 3, and the pulsed X-rays are filtered by the radiation quality 4 to generate pulsed filtered beam X-rays, thereby forming a pulsed X-ray reference radiation field.

[0029] The tube voltage range of the steady-state X-ray machine 1 is 5kV-800kV, and the tube current range is 0-800mA. Preferably, the tube voltage range of the steady-state X-ray machine 1 is 10-225kV, and the tube current range is 0-15mA, and the dual focal spot sizes are 0.4mm and 1.0mm respectively.

[0030] A key technology of the present invention is to realize the pulsed output of steady-state X-rays through a pulse shutter. The structure of the pulse shutter is as follows: Figure 2 As shown, the pulse shutter 3 is a pneumatic shutter structure, including a high-speed cylinder 31, a slide rail 32, a cylinder bracket 33 and a tungsten alloy shutter 34. The piston rod end of the high-speed cylinder 31 is connected to the cylinder bracket 33, the cylinder bracket 33 is connected to the tungsten alloy shutter, and the cylinder bracket 33 is installed on the slide rail 32. The piston rod of the high-speed cylinder 31 performs linear reciprocating motion, driving the cylinder bracket 33 to perform linear reciprocating motion along the slide rail 32, thereby driving the tungsten alloy shutter 34 to perform linear reciprocating motion. When the piston rod of the high-speed cylinder 31 is extended, the tungsten alloy shutter 34 covers the ray exit port, and the X-ray cannot be emitted from the ray exit port; when the piston rod of the high-speed cylinder 31 is retracted, the ray exit port is exposed, and the X-ray is emitted from the ray exit port, thereby realizing the pulsed output of steady-state X-rays.

[0031] The pulse width of the pulse X-ray reference radiation field is adjusted by adjusting the travel speed of the piston rod of the high-speed cylinder 31 and the shutter opening size. The travel speed range of the pulse shutter is 0.01m / s-50m / s. By adjusting the shutter opening size, a single pulse X-ray output with a pulse width of 0.1ms-10s can be achieved, and the radiation field diameter range is 7cm-70cm.

[0032] Low-energy photons account for a large proportion of the pulse X-ray energy spectrum output from the pulse shutter 3, but the transmission ability of low-energy photons is very poor and cannot be used directly. It is necessary to filter it appropriately to remove the useless low-energy part. The radiation quality 4 is used to filter the original pulse X-ray appropriately, remove the useless low-energy part, and form a pulsed filtered beam X-ray reference radiation.

[0033] In this embodiment, multiple radiation masses 4 are set up at the same time, and the performance parameters of each radiation mass are different. They are evenly distributed on the circumference of a rotatable wheel. When in use, the appropriate radiation mass is selected according to the needs to be on the axis of the radiation field to obtain different pulse filtered beam X-ray reference radiations.

[0034] The beam limiting aperture 5 is used to control the divergence angle of the pulsed filtered beam X-ray within a set range.

[0035] The stability of the pulsed X-ray field is monitored by monitoring the ionization chamber 6; scattered radiation is reduced and radiation leakage is prevented by shielding the support body 2.

[0036] With reference to the requirements of the international standard ISO4037-1, the present invention establishes narrow spectrum series pulsed X-ray reference radiation fields (N-series, L-series, H-series, W-series) and medical diagnostic series pulsed X-ray reference radiation fields (RQR-series, RQA-series, RQB-series, RQN-series, RQT-series, RQC-series) based on filtered beam X-rays. The performance parameters of the radiation quality of the pulsed X-ray part are shown in Tables 2 and 3.

[0037] Table 2 Basic parameters of RQR radiation quality in pulsed X-ray reference radiation field

[0038]

[0039] Table 3 Basic parameters of N series radiation quality in pulsed X-ray reference radiation field

[0040]

[0041] The parameter measurement method of the pulsed X-ray reference radiation field established by the device of the present invention is as follows:

[0042] (1) Pulse time measurement

[0043] The pulse time measurement system is used to measure the pulse time of the pulse X-ray reference radiation field. The pulse time measurement system consists of a scintillator detection element, a light collector, a photoelectric conversion device (Si-PIN photodiode), a preamplifier, an oscilloscope and a DC power supply. When the scintillator probe is irradiated by pulsed X-rays, fluorescence is generated. The fluorescence is transmitted to the photoelectric conversion device (Si-PIN photodiode) through the light collector to generate an electrical signal, which is displayed by the electronic system. According to the general requirements of time measurement, the test system response must be more than 3 times faster than the pulse signal to be measured. This measurement uses CsI (Tl) crystal as a detector to obtain ms-level pulse X-ray time, and uses the S3590-19 Si-PIN photodiode of Hamamatsu Company in Japan as the photoelectric converter of the CsI crystal output. The spectral response range of this type of silicon photodiode is (340~1100)nm, which is suitable for CsI crystals. Its photosensitivity is about 0.58A / W, the maximum dark current is about 10nA, and the cut-off frequency is 40MHz.

[0044] The pulse time measurement system will display the pulse X-ray output waveform on the oscilloscope, and the pulse time is calculated by the following formula:

[0045] t pulse =t a -t b (1)

[0046] In the above formula, t pulse is the pulse time, ta is the pulse start time, t b is the pulse end time. Determine the pulse time based on the pulse output waveform displayed by the oscilloscope.

[0047] (2) Pulse X-ray dose measurement

[0048] The dose of the pulsed X-ray reference radiation field is measured using a pulsed X-ray secondary standard ionization chamber. The tube voltage adjustment range of the steady-state X-ray machine is 10-225kV, the tube current adjustment range is 0-15mA, and the maximum power is 2.25kW. Under the same tube voltage conditions, the instantaneous dose rate of the pulsed X-ray can be changed by adjusting the tube current of the steady-state X-ray machine. The pulse width is determined by the running speed of the tungsten alloy shutter. When the high-speed cylinder travels at a speed of 1m / s, a single pulse X-ray output with a pulse width of 15ms can be achieved.

[0049] The pulse X-ray reference radiation field dose based on a steady-state X-ray machine was measured using an SSPR pulse X-ray flat-panel ionization chamber. The measurement unit is air kerma, and the ambient dose equivalent and personal dose equivalent can be obtained by multiplying the corresponding conversion coefficient. The distance from the measurement position to the focus of the X-ray machine is 1m.

[0050] The single pulse dose and instantaneous dose rate of part of the radiation quality of the pulsed X-ray reference radiation field are shown in Table 4.

[0051] Table 4 Pulse X-ray reference radiation field dose measurement results

[0052]

[0053] The present invention establishes a pulse reference radiation field based on a steady-state X-ray machine, which can realize the radiation performance parameter test of the nuclear radiation dosimeter under pulse dynamic parts, and solves the traceability problem of the measuring instrument for pulse radiation dose monitoring; the pulse width of the established pulse X-ray reference radiation field is adjustable between 0.1ms-10s, which can be used to carry out research on the pulse radiation response characteristics of various radiation protection instruments and personal dosimeters, and can also be used to carry out testing, calibration and verification of nuclear accident critical alarm systems.

[0054] The above embodiments are merely illustrative of the present invention, and the present invention may also be implemented in other specific ways or other specific forms without departing from the gist or essential features of the present invention. Therefore, the described embodiments should be considered illustrative rather than restrictive in any respect. The scope of the present invention should be described by the appended claims, and any changes equivalent to the intent and scope of the claims should also be included within the scope of the present invention.

Claims

1. A pulse reference X-ray reference radiation field generating device based on a steady-state X-ray machine, characterized in that: The invention comprises a steady-state X-ray machine (1) and a shielding support body (2) disposed outside the steady-state X-ray machine (1), wherein a ray exit port is formed on the shielding support body (2), and the ray exit port is located on the axis of the radiation field generated by the steady-state X-ray machine, and a pulse shutter (3), a radiation quality (4) and a beam limiting aperture (5) are disposed in sequence outside the shielding support body (2) along the axis of the radiation field of the steady-state X-ray machine, wherein the pulse shutter (3) is adjacent to the ray exit port; The continuous X-rays generated by the steady-state X-ray machine (1) are cut and output as pulsed X-rays by the pulse shutter (3), and the pulsed X-rays are filtered by the radiation quality (4) to generate pulsed filtered beam X-rays, thereby forming a pulsed X-ray reference radiation field; The pulse shutter (3) comprises a high-speed cylinder (31), the piston rod end of the high-speed cylinder (31) is connected to a cylinder bracket (33), the cylinder bracket (33) is connected to a tungsten alloy shutter, and the cylinder bracket (33) is mounted on a slide rail (32). The tungsten alloy shutter (34) is driven to perform a linear reciprocating motion by the piston rod of the high-speed cylinder (31), thereby controlling the opening and closing of the ray exit port, thereby achieving pulse output of X-rays; the pulse width of the pulsed X-rays is adjusted by adjusting the travel speed of the piston rod of the high-speed cylinder (31) and the shutter opening size; The number of the radiation masses (4) is multiple and evenly distributed on the circumference of a rotatable wheel. The performance parameters of the multiple radiation masses (4) are different. According to the needs, the appropriate radiation mass is rotated to the axis of the pulsed X-ray radiation field to obtain different pulsed filtered beam X-ray reference radiations.

2. The pulse reference X-ray reference radiation field generating device based on a steady-state X-ray machine according to claim 1, characterized in that: The travel speed range of the piston rod of the high-speed cylinder (31) is 0.01 m / s-50 m / s, and by adjusting the shutter opening size, the pulse width range of the corresponding output single pulse X-ray is 0.1 ms-10 s.

3. The pulse reference X-ray reference radiation field generating device based on a steady-state X-ray machine according to claim 1, characterized in that: The radiation mass (4) is used to filter out the low energy part of the pulsed X-rays to form pulsed filtered beam X-ray reference radiation.

4. The pulse reference X-ray reference radiation field generating device based on a steady-state X-ray machine according to claim 1, characterized in that: The number of the beam-limiting diaphragms (5) is two, and a monitoring ionization chamber (6) is provided between the two beam-limiting diaphragms (5).

5. The pulse reference X-ray reference radiation field generating device based on a steady-state X-ray machine according to claim 4, characterized in that: The divergence angle of the pulsed filtered beam X-ray is controlled within a set range by the beam limiting aperture (5); and the stability of the pulsed filtered beam X-ray field is monitored by the monitoring ionization chamber (6).

6. The pulse reference X-ray reference radiation field generating device based on a steady-state X-ray machine according to claim 1, characterized in that: The shielding support body (2) reduces X-ray scattered radiation and prevents radiation leakage.

7. The pulse reference X-ray reference radiation field generating device based on a steady-state X-ray machine according to any one of claims 1 to 6, characterized in that: The pulse X-ray reference radiation field generated by the device has a diameter ranging from 7 cm to 70 cm.

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